Corrosion is the deterioration of metals by chemical or electrochemical reaction with environmental factors. Corrosion, which is only seen in metals, occurs as a result of the reaction of the metal surface with water, acid, oxygen or different chemicals. This reaction adversely affects the physical and chemical properties of metals and causes deterioration in their structures.
Corrosion can occur wherever metals are present. Irons in the structural elements of buildings are one of the points where this event occurs. The occurrence of this event in the iron in reinforced concrete structures causes the structural elements of the structures to lose their properties and weaken. All these shorten the life of the buildings. It is possible to completely prevent this risk with the right insulation materials to be used.
What is Corrosion?
Corrosion is an event that causes metals to lose their metallic properties by electrochemical or chemical reaction with the environment in which they are located, causing their structures to deteriorate and weaken. When it continues for a long time, metals completely lose their properties and after a while they decay and disappear.
Metals inevitably corrode if the right precautions are not taken. This phenomenon, popularly known as rusting, leads to a decrease in the strength and functionality of metals. When metals become unusable, it causes environmental pollution, weakens structures and adversely affects human health.
If corrosion occurs only between the metal and its environment and no electric current occurs, the event is called chemical corrosion. In this process, when electric current occurs at different points of the metal, the event is called electrochemical corrosion.
How Does Corrosion Occur?
Corrosion occurs as a result of the combination of metal and oxygen. Oxygen and metal combine with anodic and cathodic reactions on the metal surface. As a result of this combination, a new substance emerges. For example, when iron and oxygen combine, iron oxide is formed. Iron oxide is a substance known as rust. This is why corrosion is also called rusting among the people.
These reactions are accelerated in the presence of moisture, salt water and acidic environments around the metal. Thus, rusting occurs much faster than normal and causes the metal to lose its properties in a very short time.
What are the Types of Corrosion?
There are different types of corrosion. Details on these common types are as follows:
Galvanic Corrosion
A type of corrosion that occurs when two metals have electrical or physical contact with each other and are immersed in a common electrolyte. This requires metals with different electrochemical potentials and a connection between the two. The connection is made by electrolytes such as acid or brine. It is common in marine applications, structures and pipelines.
Uniform Corrosion
It is the type that occurs at equal speed at every point of the metal surface. A homogeneous deterioration of the metal surface occurs. It is often unnoticeable and therefore negatively affects the durability and even the thickness of the metal.
Intergranular Corrosion
Occurs at the grain boundaries of the metal. Common in stainless steels and alloys after heat treatment. It damages the mechanical properties of materials and leads to the formation of cracks due to weakening.
Electrochemical Corrosion
It occurs due to cathodic and anodic reactions within the electrochemical cell. It is common in environments with moisture and water, which cause increased electrical conductivity. It is known to occur commonly in ships, underwater structures and pipelines.
What is Corrosion in Building?
Building corrosion or concrete corrosion is the deterioration of the structures of the irons in the building due to environmental influences. The irons in the columns, beams, curtains and floors are exposed to rust due to unsuitable conditions and begin to lose their durability.
This event seriously threatens the load-bearing systems of buildings. Weakened structural systems can no longer ensure building safety and buildings become risky against earthquakes. In addition, cracks and other deformations lead to aesthetically negative images.
How Corrosion Occurs in Structures?
There are different factors that cause corrosion in structures. First of all, it should be known that this event is caused by the contact of oxygen and metal and accelerated by the electrolytes in the environment. The issues that cause corrosion in structures are as follows:
- Water: Water is a critical electrolyte for corrosion. Wetting or dampness caused by water accelerates the reaction of oxygen and metal. Thus, rusting and decay occurs much faster. Rainwater, plumbing leaks and groundwater are known to be the most important causes of corrosion in structures.
- High Humidity: In environments with high humidity, it is almost inevitable for water to penetrate into the concrete. Moisture entering the concrete accelerates the combination of the metal reinforcement with oxygen and rusting occurs. This risk is extremely high in basements and below ground areas.
- Carbonation of Concrete: When concrete is not of sufficient quality, its permeability is high. In such cases, carbon dioxide in the atmosphere and substances in the concrete begin to react chemically and calcium carbonate is formed. This causes the iron in the concrete to come into contact with air and moisture more easily and rust.
- Industrial Pollutants: In areas where industrial activities are intense, air pollution is significantly higher than in other regions. In such areas, chloride and similar substances in the air adhere to the concrete surface and penetrate into it over time. This increases the risk of corrosion.
- Concrete Quality: When concrete quality is not at the desired level, pores and similar structures occur on its surface. In addition, cracks and fractures are also seen in poor quality concrete over time. All this makes it easy for water and harmful chemicals to come into contact with metals.
- Acids Acids are one of the main causes of corrosion and rusting of metals. Industrial emissions and rain acid are the main sources of acids that cause corrosion. In addition, acidic detergents and cleaning materials also cause the metal surfaces they come into contact with to rust. Many kitchen utensils with stainless surfaces lose this feature and rust due to the use of the wrong cleaning product.
- Electric Current Electric current is a factor that facilitates and accelerates electrochemical corrosion. In buildings where grounding is not done or done incorrectly, corrosion caused by electric current is much more common.
- Inadequate Insulation: Perhaps the main cause of corrosion in buildings is inadequate insulation. When the right and high quality insulation materials are not used, water and harmful chemicals reach the metals in the reinforced concrete structure and cause corrosion.
These are the main causes of what is called concrete corrosion in structures. However, since each structure has its own characteristics, the effects of these causes may differ.
The Relationship Between Corrosion and Waterproofing
There is a direct relationship between corrosion in buildings and waterproofing. By eliminating the contact of structures with water, the risk of corrosion is minimized. This is only possible by using the right insulation materials.
There are different types of products to be used for waterproofing. The appropriate ones should be preferred by looking at the point of use and needs. Details about some waterproofing materialsare as follows:
- Polyurethane Waterproofing: Polyurethane based waterproofing materials are frequently preferred for their easy applicability. Water Block is a product that offers an economical waterproofing solution. It provides waterproofing by adhering strongly to any surface.
- Polyurethane Injection: Polyurethane injection is widely used among waterproofing materials. DF PUR INJEKTION 2K Polyurethane Injection is a two-component, solvent-free, polyurethane injection resin that reacts on contact with water.
Liquid Glass: It both aesthetically enhances the areas where it is applied and provides insulation. DryFix GLASSY 100 is a product that provides transparent insulation and eliminates problems related to liquid insulation. - Cold and Pure Polyurea: Cold polyurea is an economical waterproofing system that adheres strongly to all kinds of surfaces. Pure polyurea, on the other hand, is a two-component, 100% solid, machine-applied, high performance solution based on pure aromatic polyurea, which cures in a very short time in all weather conditions and stands out with its waterproofing.
It is almost mandatory to use appropriate and quality waterproofing materials in buildings to protect against corrosion. By examining the products on our site, you can also benefit from the advantages offered by quality insulation materials.
